Magnetically coupled actuator and lead screw control for a variable pressure pilot valve

ABSTRACT

A programmable, electronically controlled sprinkler system has a hermetically sealed internal chamber which encloses all of the internal water flow, valves, mechanical and rotational components and a plurality of magnetic coupling arrangements which allow external motors to control operation of the internal mechanical components without requiring any hydraulic seals.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. ProvisionalApplication No. 62/815,726, filed Mar. 8, 2019.

BACKGROUND OF THE DISCLOSURE

Embodiments of the invention relate to water sprinkler systems, and moreparticularly to programmable electronically controlled sprinkler systemswhich are controllable to effect sprinkler direction and time ofwatering.

The design of present sprinkler systems is focused on structure whichallows the water to flow through the system and to mechanically rotatethe sprinkler head achieving a predefined of coverage pattern.Electronic controls effect the timing of when the sprinklers are turnedon and off. Distance or travel of the spray and rotation arcs of priorart systems are typically controlled mechanically with spray nozzleselection and angle, and mechanical rotational limits.

The existing systems are known to have high power requirements whichrequire wired electrical power, are known to be difficult to program andconfigure for optimal coverage and are further known to wasteconsiderable amounts of water. There is thus a continuing need forimprovements in such watering systems.

SUMMARY OF THE INVENTION

A smart sprinkler system in accordance with the present disclosuredelivers water from a pressurized water supply to any location withinits range via a spray nozzle or sprinkler head that can be rotated inany direction. The distance of the spray field is determined by thewater pressure. The term “smart”, in the context of the present system,refers to its ability to be controlled wirelessly using a “smart”device, such as a smart phone or tablet that can run an associatedapplication that communicates with the control electronics of thesystem. Once configured, the sprinkler functionality is controlled bythe device autonomously. This division of labor, the sprinkler deviceperforming the functions of the sprinkler and the phone/tablet providingthe Graphical User Interface (GUI), leverages the power of a device thatis designed specifically for providing rich and familiar userinterfaces, while alleviating the cost and complexity of providing auser interface on the sprinkler.

A defining characteristic of the sprinkler system is that it is able todeliver a small footprint of water to a specific location in areproducible manner. The sprinkler head rotates about a vertical axis,so the specification of a location is represented in polar coordinatesas an angle and a pressure, where the pressure is related to the radialdistance from the sprinkler head. The area of water striking the groundcan best be envisioned as a narrow rectangle or short line segmentradial to the nozzle. The orientation of the rectangle lengthwise alongthe radius is also intentional, as the primary means of distributing thewater in a pattern is by sweeping it about an arc. A sprinkler patternis created as a series of curves, with each curve being defined as achange of pressure and change of rotation angle. Each pressurerepresents a distance from the sprinkler head. If the pressure ischanged, but the rotation angle is not, then the movement would describea radial line segment emanating from the sprinkler head at the center.If the rotation is changed, but the pressure is not, then the movementdescribes an arc with a radius proportional to the pressure andendpoints corresponding to the starting and ending angles of rotation.If both the pressure and rotation angles change then the movementdescribes a curve that approximates an average of two arcs at the twopressures with the same rotational endpoints. These movementseffectively amount to vectors described in polar coordinates, where thechange in pressure represents the radial component and the change inrotation represents the component along an arc. Note that sufficientlysmall movements may be used to approximate straight lines. As thesprinkler describes a curve over time, a narrow band of spray isproduced along the arc component. A user is able to describe a series ofpoints and curves, which together combine into a predefined area, orwatering pattern, as the sprinkler sweeps across between each pair ofpoints in sequence.

It is also a defining characteristic of the sprinkler system that it isable to operate with only a single connection to a water source and doesnot require a connection to any external power. This allows the presentsprinkler system to be a direct replacement for a typical lawnsprinkler, which is mechanically driven entirely by the energy providedby the supply pressure of the water source. Unlike a mechanical lawnsprinkler, which only provides one pressure (that of the supply) and oneset of stops and can, therefore, only supply one pattern that is eitherroughly rectangular or circular (depending on the type), the presentsprinkler system can create arbitrarily shaped patterns. It achievesthis by using a circular lawn sprinkler mechanism to drive the rotationof the sprinkler head, but with an electric motor to actuate themechanism that controls the direction of the rotation. Additionally, thepresent sprinkler system explicitly controls the water pressuredelivered to the spray nozzle, up to the maximum of the supply pressure.The system achieves this using an adjustable piloted valve assembly,which maximizes the use of the supplied pressure to affect changes tothe valve.

Required electrical energy is harvested from two sources: a hydrogenerator in line with the water flow between the pressurized supply andthe nozzle (input and output, respectively) and a solar panel. Bothsources provide DC electricity used to power the electronics thatcomprise the control system. The hydro generator provides energy whilethe sprinkler is active (i.e. water is flowing through it) and the solarpanel captures energy from the sun, regardless of whether the sprinkleris active. Since the sprinkler is always consuming energy, the powersystem includes a rechargeable battery and a battery charge controller.Thus, the two power sources are used to power the system. Any energy inexcess of the demands of the system is put into the battery. If thesystem consumes more energy than is supplied by the power sources thenthe difference is drawn from the battery. The energy system is balanced,such that the battery is never completely drained, requiring noadditional power source under normal use.

The electrical components associated with the direct control of thesprinkler system may comprise two low-power DC motors: one for apressure control valve and the other for a diverter that controls therotational direction of the spray nozzle. The motors provide the inputto magnetic couplings. The valve control motor is used to open and closethe piloted valve incrementally and the diverter motor is used to rotatean armature to change the flow path in an oscillator which drives thesprinkler head in either direction or may hold it stationary.

The microcontroller unit (MCU) performs all functions related to thecontrol of the sprinkler system using software stored in non-volatilememory within the MCU itself. The MCU also includes storage, bothvolatile (RAM) and non-volatile, for storing data associated with therunning of the device. The MCU also provides a short-range radio used toprovide a wireless interface used by the external smart device toconfigure and control the sprinkler remotely. The firmware defines andimplements a command interface to provide these capabilities.Additionally, the MCU provides timing and counting functions that allowthe device to control when it starts or stops. It may be configured to,for example, run a user-defined pattern for a specified duration or tobe repeated a specified number of times before shutting itself off.

Accordingly, it can be seen that the present system provides severalunique and novel improvement over systems of the prior art, particularlywith respect to sealed chamber magnetic couplers which eliminate theneed for high friction seals for rotating parts and which also reducepower needs for rotating components within the sealed chambers.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present invention can be more readilyunderstood and appreciated by one of ordinary skill in the art from thefollowing descriptions of various embodiments of the invention when readin conjunction with the accompanying drawings in which:

FIG. 1 illustrates an exemplary sprinkler system block diagram inaccordance with the present invention;

FIG. 2 illustrates an exemplary configuration of the present sprinklersystem;

FIG. 3 illustrates an exemplary spray pattern using an angled nozzlehead

FIG. 4 diagrammatically illustrates an area to be watered overlaid withan exemplary programmed watering pattern which can be implemented withsoftware for controlling the present invention;

FIG. 4A illustrates rotation of the sprinkler head and adjustments ofwater pressure for distance to transcribe the desired watering pattern;

FIG. 4B-C diagrammatically illustrate another exemplary programmedwatering pattern using a different algorithm where the pressure androtation are changing concurrently in a vector system with polarcoordinates;

FIG. 5 is a bottom perspective view of an exemplary magnetic couplingand limit switch system illustrating the external drive components;

FIG. 6 is a side view thereof illustrating both the external drivecomponents and the internal follower components;

FIG. 7 is a top perspective view thereof illustrating the internalfollower arm and mechanical stops;

FIG. 8 is a top view thereof;

FIG. 9 is an exploded perspective view thereof illustrating thealignment of the coupling magnets captured in the internal and externalcoupling components;

FIGS. 10A and 10B illustrate coupled rotation of the magnets when freelymoving and continued rotation and axial translation of the externalmagnet when the internal magnet is restricted by a mechanical stop;

FIG. 11 illustrates an exemplary pilot valve which is adapted forvariable pressure control with a magnetically actuated lead screw;

FIG. 12 illustrates a full assembly view of the pilot valve pressurecontrol;

FIG. 13 is a perspective view thereof shown partially in transparency;

FIG. 14 is a cross-sectional view thereof taken along line 14-14 of FIG.12;

FIG. 15 is an exploded perspective view of the valve control mechanismfor the pilot valve;

FIG. 16 is a plan view of an exemplary oscillator/diverter mechanism inaccordance with the present invention;

FIG. 17 is another plan view thereof shown partially in transparency;

FIG. 18 is a bottom perspective view thereof showing the external drivecomponents of the magnetic coupling system;

FIG. 19 is a perspective view of the diverter assembly;

FIG. 20 is an exploded perspective view of the diverter control magneticcoupling input;

FIG. 21 is a top view of the diverter control;

FIG. 22 is an exploded perspective view of the turbine chamber inposition above the output of the diverter; and

FIG. 23 is a top view thereof showing the relationship of the diverterarmature and the flow ports of the oscillator chamber.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Certain exemplary embodiments will now be described to provide anoverall understanding of the principles of the structure, function,manufacture, and use of the device and methods disclosed herein. One ormore examples of these embodiments are illustrated in the accompanyingdrawings. Those skilled in the art will understand that the devices andmethods specifically described herein and illustrated in theaccompanying drawings are non-limiting exemplary embodiments and thatthe scope of the present invention is defined solely by the claims. Thefeatures illustrated or described in connection with one exemplaryembodiment may be combined with the features of other embodiments. Suchmodifications and variations are intended to be included within thescope of the present disclosure. Further, in the present disclosure,like-numbered components of the embodiments generally have similarfeatures, and thus within a particular embodiment each feature of eachlike-numbered component is not necessarily fully elaborated upon.Additionally, to the extent that linear or circular dimensions are usedin the description of the disclosed systems, devices, and methods, suchdimensions are not intended to limit the types of shapes that can beused in conjunction with such systems, devices, and methods. A personskilled in the art will recognize that an equivalent to such linear andcircular dimensions can easily be determined for any geometric shape.Further, to the extent that directional terms like top, bottom, up, ordown are used, they are not intended to limit the systems, devices, andmethods disclosed herein. A person skilled in the art will recognizethat these terms are merely relative to the system and device beingdiscussed and are not universal.

Referring generally to FIGS. 1 through 4, a smart sprinkler system inaccordance with the present disclosure is illustrated and generallyindicated at 10. The smart sprinkler system 10 delivers water from apressurized supply 12 to any location within its range via a spraynozzle or sprinkler head 14 that can be rotated in any direction. Thespray nozzle 14 includes at least one, but preferably a plurality of,angled orifices 16 which create an elongated, somewhat narrow sprayfield 18 as generally illustrated in FIG. 3. The distance “D” of thespray field 18 is determined by the water pressure. The term “smart”, inthe context of the present system 10, refers to its ability to becontrolled (wired or wirelessly) using a “smart” device 20, such as asmart phone or tablet that can run an associated application thatcommunicates with the control electronics 22 of the system 10. Thepresent system is implemented in a wireless configuration, and inparticular, the wireless interface implemented in this exemplary systemis a Bluetooth Low Energy (BLE) interface which is common to thecategory of personal devices known as smart devices (e.g. mobile phones,tablets).

It should be understood that other wired and wireless interfaces andstandards could also be implemented with the same functionality. Indeed,the smart sprinkler system 10 requires a smart device 20 to control andconfigure the sprinkler system 10 using an associated application asnoted above. Any electronic interface that is capable of supportingcommands is a viable possibility. Once configured, much of the sprinklerfunctionality is controlled by the device autonomously. This division oflabor, the sprinkler device 10 performing the functions of the sprinklerand the/phone/tablet device 20 providing the GUI, leverages the power ofa device that is designed specifically for providing rich and familiaruser interfaces, while alleviating the cost and complexity of providinga user interface on the sprinkler.

A defining characteristic of the sprinkler system 10 is that it is ableto deliver a small footprint 18 of water to a specific location in areproducible manner. There are several possible methods foraccomplishing this goal.

The sprinkler head 14 rotates about a vertical axis, so thespecification of a location can be represented in polar coordinates asan angle and a pressure, where the pressure is related to the radialdistance D from the sprinkler head. The footprint of water striking theground can best be envisioned as a narrow rectangle or short linesegment radial to the nozzle 14. The footprint 18 is by design andrepresents a balance between having a fine resolution for placing waterand avoiding too high a density of water striking the ground at a singlelocation. The orientation of the rectangle lengthwise along the radiusis also intentional, as the primary means of distributing the water in apattern is by sweeping it over a curve.

In a first exemplary method, a sprinkler pattern is created as a seriesof arcs 24 a, 24 b, 24 c (FIGS. 4 and 4A), with each arc being definedas a pressure and two angles. The pressure represents the radius of thearc and the two angles represent the left and right ends or stops 26A,26 b of the associated arc. As the sprinkler describes the arc 24 overtime, a narrow band of spray 18 is produced. A user is able to describea series of arbitrary concentric arcs 24, which together combine into anarbitrary defined area as the sprinkler sweeps across each arc insequence.

In a second exemplary method, the curve is defined by two points P1, P2with a change in pressure and change in rotation angle, relative to thesprinkler head S, which defines the center of a circle. The curve is,essentially a vector v in polar coordinates with a radial component rand an arc component a (FIG. 4C). A sprinkler, or watering, pattern iscreated as a sequence of such vectors 24 a . . . 24 n (FIG. 4B). As thesprinkler describes each curve 24 over time, a narrow band of spray 18is produced. In describing a sequence of curves, a path is followed,which in totality deposits a volume of water on an area. A user is ableto describe an arbitrary sequence of these curves 24 by defining thepoints P1, P2, . . . Pn. A schematic illustration of an area to bewatered overlaid with such a sequence 24 a . . . is illustrated in FIG.4B.

It is also a defining characteristic of the sprinkler system 10 that itis able to operate with only a single connection to a water source 12and in some embodiments does not require a connection to externalelectric power. This allows the present sprinkler system 10 to be adirect replacement for a typical lawn sprinkler, which is mechanicallydriven entirely by the energy provided by the supply pressure of thewater source. Unlike a mechanical lawn sprinkler, which only providesone pressure (that of the supply) and one set of stops and can,therefore, only supply one pattern that is either roughly rectangular orcircular (depending on the type), the present sprinkler system cancreate arbitrarily shaped patterns. It achieves this by using a circularlawn sprinkler mechanism to drive the rotation of the sprinkler head 14,but with an electric motor (oscillator/diverter mechanism 300—describedbelow) to actuate the mechanism that controls the direction of therotation. Additionally, present the sprinkler system 10 explicitlycontrols the water pressure delivered to the spray nozzle, up to themaximum of the supply pressure (i.e. there is no pump to add pressureabove that of the supply). The system achieves this using an adjustablepiloted valve (pilot valve assembly 200), which maximizes the use of thesupplied pressure to affect changes to the valve. In short, themechanism is designed to use as little energy as practicable.

In the present wireless configuration, required electrical energy isharvested from two sources: a hydro generator 28 in line with the waterflow between the pressurized supply 12 and the nozzle 14 (input andoutput, respectively) and a solar panel 30. Both sources provide DCelectricity used to power the electronics 22, MCU/memory 32, wirelessradio 34, motor control 36 and sensors 38 that comprise the controlsystem. The hydro generator 28 provides energy while the sprinkler isactive (i.e. water is flowing through it) and the solar panel 30captures energy from the sun, regardless of whether the sprinkler isactive. Since the sprinkler is always consuming energy, the power systemincludes a rechargeable battery 40 and a battery charge controller 42.Thus, the two power sources 28. 30 are used to put energy into thebattery 40, even as the device consumes energy. The energy system isbalanced, such that it requires no additional power source under normaluse. There is, however, an electrical connection (not shown) forattaching to an external charger for expediting an initial charge beforefirst use or after storage.

In a wired system, the rechargeable battery 40, charge controller 42,hydro generator 28 and solar panel 30 could be eliminated to reducecomplexity and cost.

The electrical components associated with the direct control of thesprinkler system 10 may comprise two low-power DC motors: one motor 202for a piloted pressure control valve system 200 (See FIGS. 11-15) andthe other motor 302 for a diverter system 300 (See FIGS. 16-23) thatcontrols the rotational direction of the spray nozzle 14. The motors202, 302 provide the input to magnetic couplings 204, 304 (furtherdescribed below). The speed, duration and direction of the motors 202,302 are controlled by algorithms running on a Microcontroller Unit (MCU)32. The valve motor 202 is used to open and close a piloted valve system200 incrementally and the diverter motor 302 is used to rotate anarmature of the diverter assembly 300 to change the flow path in anoscillator which drives the sprinkler head 14 in either direction or mayhold it stationary.

In order to provide closed loop control over the system, there are twosensors: a pressure sensor 400 and a magnetic rotational sensor 500. Thepressure sensor 400 is embedded in the oscillator chamber of theoscillator/diverter assembly 300 and measures the water pressuredelivered to the nozzle 14. When the desired pressure setpoint has beenconfigured, the pressure sensor 400 supplies input to the algorithm,which opens and closes the pressure control valve 200 to maintain thenozzle pressure about the setpoint within a hysteresis range. Thisallows a pressure to be maintained without calibration of the supplypressure and as the supply pressure changes over time. Note that theoutput pressure is limited at an upper end by the native supply pressure(i.e. there is no mechanism for increasing the pressure beyond thesupply pressure).

It should also be noted that additional environmental sensors 39, orsmart sensors may also be deployed with and communicate with the presentcontrol system 32 (wired or wirelessly) to provide additionaloperational input. Sensors 39 may comprise temperature sensors,atmospheric pressure sensors, light sensors, rain sensors, moisturesensors, infra-red heat sensors etc. to provide additional inputs tocontrol or modify run days, run times, or run locations as configured.

The magnetic rotational sensor 500 is external to the oscillator chamberof the oscillator/diverter assembly 300 and in line with a magnet thatis mechanically held to the rotational axis of the sprinkler head 14 orindirectly in correspondence with the sprinkler head 14. The magneticfield is diametric to the axis of rotation, which allows the sensor 500to determine the angle of rotation of the sprinkler head 14 within aresolution less than one degree. This allows the algorithm to determinewhen the sprinkler head 14 has rotated to a desired angle and to thenchange the direction of rotation or stop the rotation using the motor302 associated with the diverter armature.

The MCU 32 performs all functions related to the control of thesprinkler system 10 using software stored in non-volatile memory(firmware) within the MCU itself. The MCU 32 also includes storage, bothvolatile (RAM) and non-volatile, for storing data associated with therunning of the device (e.g. the data defining a user-defined pattern).The MCU 32 also provides the radio 34 (Bluetooth) used to provide awireless interface used by the external smart device 20 to configure andcontrol the sprinkler remotely. The firmware defines and implements acommand interface to provide these capabilities. Additionally, the MCU32 provides timing and counting functions that allow the device tocontrol when it starts or stops. It may be configured to, for example,repeat a user-defined pattern (See FIG. 4) for a specified duration or aspecified number of times before shutting itself off.

FIG. 1 shows a block diagram of the components of the sprinkler 10 thatenable all of the capabilities described above. The ultimate purpose ofthe system 10 is to deliver water from a supply to desired locations.FIG. 1 illustrates the path of the water flow (thicker arrows “W”)through the system as it controls the water and extracts energy from thewater to power the system. FIG. 1 also illustrates the path of energy(thinner arrows “E”) as it is generated from the hydro generator 28 andsolar panel 30, stored in the battery 40 and utilized. The system isalso responsible for control, so the diagram shows the path of thecontrol and data signals (lines “C”). Finally, the system offloads theresponsibility for providing a user interface to the external smartdevice 20 and the wireless control interface for communication with theexternal smart device 20 is also illustrated.

Referring to FIG. 2, the water supply flows, first, into the pressurecontrol valve assembly 200. The pressure control valve 200 is capable ofshutting off the water supply entirely as well as providing a desiredset water pressure from zero up to roughly the maximum limit of thenative supply pressure. The water then flows into the hydro generator28. A minimum amount of water pressure is required before the turbineinside the generator 28 will spin. Once it begins to spin, the outputenergy is relative to the speed of rotation or the output pressure ofthe control valve assembly 200. The water flow exits the hydro generator28 and enters the oscillator/diverter assembly 300, which determines thedirection of rotation of the sprinkler head 14.

The oscillator/diverter 300 achieves this by directing water throughports that lead to an oscillator turbine. Generally, each port directswater to one side or the other of the turbine, each port correspondingto one direction of rotation. The rotating turbine provides themechanical energy to turn the sprinkler head 14. A diverter chamber alsoprovides a direct path to the sprinkler head through a pressure reliefvalve. This allows excess water pressure to bypass the oscillator, whichlimits the maximum speed of rotation of the sprinkler head 14.

The electrical energy of the system includes rechargeable battery 40,allowing the sprinkler system 10 to be run over a wide range ofcircumstances. The battery 40 allows the energy to be budgeted, so thatthe energy generated does not have to be explicitly associated withenergy consumption of specific components. Rather, generated energy isadded to the battery 40 and energy consumed comes from the battery 40.This is all managed by the battery charge controller 42, which alsoperforms voltage regulation. The battery charge controller 42 directsenergy from the hydro generator 28, which is in the range of 0-5V, andthe solar panel 30, which is in the range of 0-6V, into the rechargeablebattery 40 (See FIG. 1). The variability of voltage stems from the factthat the generator 28 is not always running, and its RPMs are relativeto the output water pressure. The solar panel 30 only produces energyduring the day and its output is relative to the amount of directsunlight. The energy consumed depends on whether the sprinkler isrunning. When it is running, the electronics associated with the motors202, 302 and the sensors 400, 500 require 5V and represent the bulk ofthe energy consumption. The motor control circuit 36 and the sensors400, 500 are powered only while the sprinkler is active. The motors 202,302, which are the greatest consumers of energy by a factor of 10 areonly driven intermittently and for relatively short durations. The MCU32, which includes the radio 34, is always consuming some amount ofenergy, even when the sprinkler is off. Running at 3.3V, the energyconsumption is less at its maximum, when the radio 34 is actively linkedto the external smart device 20, than the electronics. The energyconsumption is smaller when the system 10 is running autonomously versuswhen the system 10 is being remotely controlled. The control signalsthat trigger the motor driver and sense the output of the pressure androtation sensors are components of this low voltage/power consumption.

Turning now to FIGS. 5-10, an exemplary magnetic coupling and switchassembly for use with a sealed chamber system is generally indicated at100. The assembly 100 is generally used to transfer a rotationalmechanical input force that is external to a sealed chamber 102 to arotational mechanism that is internal to the chamber 102 which may befilled with fluid 104 under pressure. The exemplary embodiment shown inFIGS. 5-10 is a universal configuration that could be used in any sealedchamber system to translate external motion to an internal component andto provide a linear (axial) switching actuator external to the chamber102. These general magnetic coupling and actuator principles are used inconjunction with two separate systems described with the present systemhereinafter. First, for rotation of the lead screw of a variablepressure pilot valve system generally indicated 200 (FIGS. 11-15).Second, for rotation of an oscillator/diverter lever in a water driventurbine rotation system 300 for the spray nozzle (FIGS. 16-23).

The magnetic coupling assemblies have the following characteristics:

The internal chamber 102 is hermetically sealed. There are no mechanicalcomponents penetrating the chamber which would require hydraulic seals.

The connection between the external and internal members introduceminimal friction, due to the elimination of seals and due to the forcevectors associated with the magnetic fields.

The magnetic coupling uniquely provides the ability for an externalsensor to detect when the internal mechanism has reached a hard stop.

The magnetic coupling also inherently functions as a safety clutch,allowing the coupling to disengage without damage or wear.

FIGS. 5-8 illustrate the components that are both external to thechamber 102 and internal to the chamber. The boundary between internaland external is defined by the wall 106. The inside of the chamber 102being above the wall 106 and further defined by walls 108 illustrated inbroken line in FIG. 6. In the drawing figures, the external componentsare below the boundary wall 106. The active external components aremounted on a fixed stand 110, which maintains the position andorientation of the external components relative to each other and to theinternal components. The exemplary mechanism is driven by a reversiblemotor 112. A motor gear 114 is mounted to the motor shaft (not shown).The motor gear 114 engages with and drives a magnetic coupling gear 116.The magnetic coupling gear 116 has a square hole 118 traversing it fromtop to bottom (See FIG. 9). In this hole, is an external square magnet120 (FIG. 9) abutting the chamber boundary wall 106 and a magnet adapter122 (also in FIG. 9) that couples the magnet 120 to a limit switch 124.Note that a bracket holding the limit switch 124 is not shown. Themagnet 120 and the magnet adapter 122, being square are not able torotate freely within the magnetic coupling gear 116, so that therotation of the magnetic coupling gear 116 is transmitted to the magnet120 and the magnet adapter 122, making them also driven by the couplinggear 116. The magnet 120 and the magnet adaptor 122 can move freely inthe direction perpendicular to the chamber boundary wall 106 (axiallyalong the axis of rotation of the magnetic coupling gear 116). Thisaxial motion of the magnet 120 causes the limit switch 124 to actuate,closing and opening as the magnet 120 and magnet adaptor 122 move awayfrom and toward the chamber boundary wall 106, respectively.

FIGS. 7-9 best illustrate the components that are internal to thechamber 102. The chamber boundary wall 106, as shown, incorporates awell 126 that holds a rotating armature 128 in place. The armature 128sits inside a bushing 130 inside the well to reduce friction. The well126 also reduces the thickness of the boundary wall 106. The armature128 includes a square socket 132 that captures another internal squaremagnet 134 (best seen in FIG. 9). Opposite the well, an axle 136supports the rotation of the armature 128 on an axis perpendicular tothe chamber wall 106. The axle 136 is captured by a fixed mount 138 anda washer 140. The mount 138 incorporates stops 142 a, 142 b thatrestrict the rotation of the armature 128 (see FIG. 8).

FIG. 9 presents a simplified exploded view that shows the alignment ofthe rotational components of the assembly; both internal and external tothe chamber 102. The components below the boundary wall 106 are externalto the chamber 102 and those above are internal. The boundary wall 106is shown in cross section and shows the reduced thickness of theboundary wall at the bottom of the well 126 in which the internalcomponents are seated. The motor gear 114 is shown for reference withoutthe motor 112 that drives it.

Magnetic coupling is effected by the external magnet 120 and theinternal magnet 134. The poles of the magnets 120, 134 are parallel tothe boundary wall 106. In the diagram, they are shown in phase; thenorth and south poles of the external magnet 120 are aligned with thesouth and north poles, respectively, of the internal magnet 134. Thissupplies the maximum attractive force normal to the boundary wall 106with a net torque of zero about the center line (axis).

The external magnet 120 is captured by the square hole 118 in the magnetcoupling gear 116. As the magnetic coupling gear 116 is driven by themotor gear 114, the magnet 120 is correspondingly rotated about thecenter line. The magnet adapter 122 is also located in the square hole118, adjacent to the magnet 120 and between the magnet 120 and the limitswitch 124. It is also square and rotates in correspondence to themagnetic coupling gear 116 and the magnet 120. It serves to mate thesquare magnet 120 to the round button on the limit switch 124. Themagnet 120 and magnet adaptor 122, while rotationally restricted, arefree to move normal to the boundary wall 106.

Inside the chamber 102 (above the wall 106), the internal magnet 134 iscaptured by the square socket 132 in the rotating armature 128. Thearmature 128 is seated in the well 126 of the boundary wall 106 insidebushing 130, which allows the armature 128 to rotate freely, incorrespondence with the rotation of the internal magnet 134. Thearmature 128 is secured at the surface opposite the boundary by the axle136 and washer 140 held by the fixed mount 138. This arrangement allowsthe armature 128 to rotate but restricts the movement of the armature128 normal to the boundary wall 106.

Turning to FIGS. 10A-10B, the behavior of the magnetic coupling isdriven by the motor 112, which rotates the motor gear 114. The motorgear 114, in turn, rotates the external magnet coupling gear 116, whichrotates the external magnet 120. As the external magnet 120 rotates, itbecomes out of phase with the internal magnet 134. The force vectorassociated with the magnets 120, 134 is proportionally skewed fromnormal and develops a rotational component. The resultant torqueincreases as the phase angle increases. At some point, the torqueincreases enough to rotate the internal magnet 134 (See FIG. 10A). Theinternal magnet 134 rotation drives the armature 128, accordingly.

Rotation of the armature 128 is restricted by stops 142 a, 142 b (seeFIG. 8). Once the coupling is rotated to the point of contacting a stop142, the armature 128 can no longer rotate. At this point, the externalmagnet 120 continues to be driven, increasing the phase angle betweenthe two magnets 120, 134. When the phase angle increases to 90 degrees,the force vector becomes completely rotational; there is no force normalto the boundary. As the angle increases beyond 90 degrees, the forcenormal to the boundary reverses, becoming repulsive. At some point, therepulsive force become large enough to push the external magnet 120 awayfrom the boundary wall 106 (see FIG. 10B). The repulsive force istransmitted through the magnet adapter 122. At some point, the repulsiveforce increases enough to force axial movement of the magnet 120 andmagnet adapter 122 and activate the spring-loaded limit switch 124. Theactivation of the limit switch 124 is detected electronically, and themotor 112 is stopped.

The motor 112 is then reversed via the electronics, which decreases thephase angle. As the phase angle decreases, the repulsive force decreasesuntil it is nullified at the 90 degree phase angle. As the motor 112(and external magnet 120) continues to rotate then the force becomesattractive and increases to its maximum at the zero degree phase angle.At some point, the external magnet 120 moves back toward the boundarywall 106 and releases the limit switch 124. The motor 112 is stoppedagain, once the limit switch 124 is deactivated.

This reverse motion that is terminated with the release of the limitswitch 124 is called the back-off period. When rotating the couplingtowards one of the stops 142, the external magnet 120 is intentionallyover-rotated after the armature 128 is physically stopped. Theover-rotation causes an increase in the phase angle. Since the limitswitch 124 cannot be activated, except via a repulsive force between themagnets 120, 134, the limit switch 124 is not engaged until the phaseangle exceeds 90 degrees. The limit switch 124 activation marks thebeginning of the back-off period, when the motor 112 is reversed. Thelimit switch 124 cannot be disengaged until the repulsive force isremoved and the magnetic force transitions from repulsion to attraction.Therefore, the limit switch 124 is released when the phase angle isreduced to less than 90 degrees, which marks the end of the back-offperiod. At the end of the back-off period, the phase angle is such thatthe magnetic force vector holds the armature 128 against the boundaryand against the stop 142. Note that this assumes that the motor 112 andmotor gear 114 are locked in position.

In alternative arrangements, the limit switch 124, which operates tosense armature 128 position, could be replaced with a solid statesensor, such as optical or magnetic sensors. For example, for an opticalsensor system the chamber boundary wall 106 separating the magnets120,134 could be optically clear. There could be optical sensors (2)(not shown) located strategically at the hard stops inside the chamber102. The sensor could then pick up on the armature 128 inside being inposition at the hard stop 142. From a power resource view, even thoughthese sensors are, themselves, consuming energy, it would actually be awin energy-wise because the limit switch 124 requires the motor 112 tobe over-rotated to activate the limit switch and then the motor must bereversed to perform the back-off movement. The extra back and forthmovement represents an additional 180+ degree movement that would not berequired if using such an optical solid state sensor. Since the motoritself is a much larger consumer of energy, the extra movement iscostly. Also, the sensors can be turned off until they are actuallyneeded (i.e. just before the motor movement). On balance, using a solidstate sensor may be a significant improvement energy-wise and time-wise,since the motor over rotation movement does take time.

As noted, the generic magnetic coupling system 100 described above isuseful in any sealed chamber system where there is a need to reduce sealand friction between moving parts. Further exemplary coupling systemsare described below in connection with the piloted valve system 200 andthe oscillator/diverter assembly 300.

Referring now to FIGS. 11-16, there is shown and described an exemplarypressure control valve assembly 200 controlled by magnetic couplingassembly 204 having the operational characteristics as generallydescribed hereinabove.

The pressure control valve 200 adjusts the water pressure delivered tothe spray nozzle 14. The distance of the spray is proportional to thepressure. In the exemplary system, the valve 200 is controlled by amotor 202, making it capable of being controlled algorithmically bymicroprocessor 22. The system 200 incorporates pressure sensor 400located adjacent the nozzle 14, which allows the system to operate as aclosed loop with respect to water pressure.

The basis of the control valve 200 is a pilot valve 206 which is used tocontrol the water pressure delivered to the sprinkler head 14. The pilotvalve 206 may comprise three chambers: the input chamber 208, the outputchamber 210 and the control chamber 212 (see FIGS. 13-14), attached tothe top of a valve seat 214. The input chamber 208 is supplied withwater through an input port 216. The pressure in the input chamber 208is always the maximum pressure, which is referred to as the supplypressure. The output chamber 210 is vented to the atmosphere via anoutlet 218 and, ultimately, to the spray nozzle 14. Atmospheric pressureis considered the zero pressure.

When the valve 200 is closed, the pressure in the output chamber 210 iszero. When the valve 200 is open, there is, typically, back pressure dueto the relatively narrow orifice of the nozzle 14. Therefore, the outputpressure may be greater than zero, but is always less than the supplypressure.

The primary flow of water flows between the input chamber 208 and theoutput chamber 210 directly when the valve is open. A secondary flowpath is through the control chamber 212, which is separated from theinput/output chambers 208, 210 by a flexible diaphragm 220 thatincorporates into it a rigid stabilizer 222. The stabilizer 222 isconnected to the diaphragm 220 by a plurality of circumferentiallyspaced posts 223 (only one visible) which are press fit throughcorresponding holes 225 in the diaphragm 220. Four points of connectionprovide higher rigidity to the diaphragm 220, prevent vibrationalinstability caused by water flow and allow the valve to stabilize in thedesired position more quickly.

Water flows into the control chamber 212 through an input pilot hole224, which is always open. Pilot hole 224 extends through one of theconnection posts 223. The water flows from the control chamber 212 tothe output chamber 210 via an output pilot hole 226, which may be openedor closed by a plug 228.

The benefit of the pilot valve arrangement is that a very small amountof energy is necessary to open or close it. The control input is amatter of opening or closing the output pilot hole 226 using the plug228. The amount of energy involved is very small because the forcenecessary is a product of the very small area of the output pilot hole226 and the pressure differential between the control chamber 212 andthe output chamber 210. Once the pilot hole 226 is opened or closed, theprimary flow of water between the input chamber 208 and output chamber210 is affected by the position of the diaphragm 220, which is afunction of the force differential on the two sides of the diaphragm220. On one side of the diaphragm 220, the force is a product of thearea of the diaphragm 220 and the pressure in the control chamber 212.On the other side, the total force is the sum of the force on the areaadjacent to the input chamber 208 and the force adjacent to the outputchamber 210. Note that the area adjacent to the input chamber 208 issignificantly larger than the output area.

When the plug 228 is blocking the output pilot hole 226, the input pilothole 224 causes the input chamber 208 and control chamber 212 toequalize, so the forces on both sides of the diaphragm 220 correspondingto the input area are equal. Since the output pressure is always lessthan the supply pressure, the area adjacent to the output chamber 210 isless than the corresponding area in the control chamber 212. Thisdifferential causes the diaphragm 220 to press toward the output port218, restricting water flow and, ultimately, closing and sealing theoutput port 218. When the plug 228 is not blocking the output pilot hole226, the pressure in the control chamber 212 equalizes with the outputchamber 210. In this state, the force on both sides of the diaphragm 220adjacent to the output area is equal. Since the control chamber pressureis less than the input chamber pressure, the force on the area adjacentto the input chamber 208 is larger on the input chamber side and thediaphragm 220 is pushed away from the output port 218, allowing morewater to flow. Note that when the diaphragm 220 is fully open, there isnecessarily a pressure differential between the supply pressure and thecontrol/output pressure because it is the differential that is holdingthe diaphragm open. That means there is a small loss of pressure whenusing this type of valve.

FIGS. 12-14 show the full valve assembly 200 with the pilot valvemechanism at the bottom with its input port 216. The basic function ofthe pilot valve chambers 208, 210, 212 and diaphragm 220 is conventionalin the art. However, the method of controlling the valve 200 is unique.The control chamber 212 is comprised of two parts 212 a, 212 b, asshown, and encompasses the control components of the valve. The externaldrive for movement of the plug 228 is supplied via a magnetic coupling100 generally as described hereabove, the external parts of which areshown and include motor 202, stand 230, drive gear 232, magneticcoupling gear 234, external magnet 236, magnet adapter 238 and limitswitch 240. The internal parts of the magnetic coupling 100 drive acontrol mechanism 242 that results in the plug 228 moving normal to theoutput port of the diaphragm 220.

FIG. 15 shows the control mechanism 242 internal to the control chamber212. The mechanism 242 is driven rotationally by the external magnet 236(FIGS. 12-14), causing an internal magnet 244 to rotate, accordingly.The internal magnet 244 is captured in a square socket at the top of amagnet adapter 246. The magnet adapter 246 rotates within bushings 248and 250 at top and bottom respectively inside a cylindrical void in thecontrol chamber housing 212 (FIG. 14). The magnet adapter 246incorporates slots 252 that trap a control arm 254 that is embeddedradially in a threaded leadscrew 256. The leadscrew 256 engages a nut258 that is captured by the control chamber housing 212. Two bushings260 a, 260 b provide the bearing surface between the rotating magnetadapter 246 and the stationary nut 256. The bottom of the leadscrew 256incorporates a flange 262 around which the rubber plug 228 is molded. Aleadscrew guide 264 ensures the plug 228 is centered on the output pilothole 226. It also serves to lock the diaphragm 220 in place in the pilotvalve mechanism. Note that it is stationary.

The pilot valve control mechanism 200 operates in the same manner as themagnetic coupling mechanism 100 described hereinabove. The externalmotor 202 drives the external magnetic coupling gear 234 and externalmagnet 236, which then drives the internal magnet 244. The square magnet244, being trapped in a square socket rotates the magnet adapter 246,which rotates the leadscrew 256 via the control arm 254. As theleadscrew 256 turns in the trapped nut 258, it moves up and downrelative to its rotational axis. This causes the plug 228 to unblock andblock the output pilot hole 226, accordingly. When the pilot hole 226 isunblocked, the diaphragm 220 rises and increases water flow through thevalve 200. When the diaphragm 220 rises and contacts the plug 228, thepilot hole 226 is blocked, and the diaphragm 220 is pushed back down bythe control chamber pressure and the water flow decreases. Asequilibrium is reached, the resulting behavior is that the diaphragm 220follows and is positioned by the control mechanism 242. This allows theexternal motor 202 of the magnetic coupling arrangement 204 toeffectively control the water flow through the valve 200 and,ultimately, the water pressure delivered to the sprinkler nozzle 14.

The pressure control valve 200 uses the magnetic coupling 204 for thecontrol input and includes limit switch 240 as also described above. Thelimit switch 240 is not used to control the variable pressure, but it isused to ensure that the valve 200 is closed. When the leadscrew 256 isdriven all the way to the closed position then it can no longer rotate.The external magnet 236 will continue to rotate and the magnets 236, 244will become out of phase. Eventually, the phase angle will become largeenough to force an axial repulsion and activate the limit switch 240,which will be detected, indicating that the valve 200 is completelyclosed. Likewise, when opening the valve 200, activation of the limitswitch 240 will occur when the valve is opened to its mechanical limit.

An interesting benefit to this arrangement is that pilot valves requirea minimum amount of pressure to stay closed. For example, if you connectone to a water supply that is off and then turn the supply on, you willtypically get a short burst of water and then the valve will seal. Thatdoes not happen with this implementation because the leadscrew 256mechanically holds the diaphragm 220 closed.

With respect to the use of alternate sensors in the pressure controlvalve 200, which uses a lead screw 256, it would make sense to keep thelimit switch 240 because the hard stops are only used to detect closingthe valve and opening it to its maximum travel. However, it could stillbenefit from using an optical sensor, though. For example, if thecontrol chamber 212 has an optically clear window then the lead screwtravel could be monitored by an encoder. That is typically implementedby including lines on the shaft that can be counted by the sensor. Thisallows for tracking exactly how much the screw has rotated inside thechamber.

While the present pressure valve embodiment 200 is illustrated anddescribed as being controlled by a motor assembly 202, the valve 200could be manually controlled or controlled by other actuators. Forexample, a manually controlled pilot valve assembly 200 (without motoror without motor and gears, i.e. manually rotating the external magnetitself) could find use in other applications as a conventional faucetvalve or spigot (not shown).

Turning now to FIGS. 16-23, there is illustrated and described anoscillator/diverter assembly 300 which is based on a water turbinerotation mechanism wherein the position of a diverter arm iselectronically controlled by a magnetic coupling mechanism 304 inaccordance with the above teachings. The assembly 300 generally includesdrive motor 302, the magnetic coupling assembly 304, a diverter assembly306 and an oscillator drive assembly 308.

The oscillator drive portion 308 is a water powered turbine motor thatrotates a shaft 310 and neck 312 to which spray nozzle 14 is secured.The rotation thereby provides the ability to direct spray in differentdirections. The oscillator drive portion 308 incorporates an assembly ofcomponents that allow the drive to reverse the direction by directingthe flow of water in one of two orientations causing a turbine wheel 314to rotate in one of two directions, accordingly. The turbine wheel 314provides the rotational input force to the water powered motor, soreversing the turbine direction also reverses the motor direction. Theassembly which is used to change the motor direction is, therefore, thediverter assembly 306.

The diverter assembly 306 allows the direction change to occur as aresult of electrical input to the reversible electric motor 302. Theelectric input is controlled by electronics, which allows the directionof the oscillator 308 to be controlled via electronic input, includingmicroprocessor control. An additional benefit of this type of control isthat the diverter 306 includes a neutral or idle position. That is, thewater flow can be directed equally to both sides of the turbine wheel314, creating a net zero force in either direction causing the waterpowered motor to stop. It is also possible to control the speed of thewater flow in either direction, thereby providing the ability to use thediverter 306 as a speed control for the water powered motor.

FIGS. 16-18 shows various views of entire oscillator/diverter 300 forreference including a transparent elevation view.

The input to the assembly, as shown, is a standard threaded garden hoseconnector 316, although it could be any suitable connector or integrateddirectly into a common housing downstream of the pressure control valve.This is the supply pressure. Varying this pressure with the pressurecontrol valve 200 affects the output pressure of nozzle 14 and, thus,the distance of the water sprayed from the nozzle 14. Varying the supplypressure will also affect the speed of the water powered motor and aminimum pressure must be supplied for the motor to turn.

The flow of water initially passes into a diverter chamber 318 throughan input port 320 and is directed through one of two exit ports 322, 324in a boundary wall 326 between the diverter chamber 318 and a turbinechamber 328 in the oscillator drive portion 308. The water flows acrossand rotates the turbine wheel 314 (assuming the diverter is not in theidle position). The water then flows through another boundary wall 330into an oscillator chamber 332 containing a gear train 334. The nozzle(not shown) is mounted to the neck 312.

There is also a pressure relief valve 338 that provides an alternativepath directly from the diverter chamber 318 to the neck 312 for water atexcessive supply pressures that might, otherwise, overwhelm thediverter/oscillator 300. The pressure relief valve 338 essentially actsas a rotation speed limiter without restricting nozzle pressure. Notethat restricting the nozzle pressure would restrict the maximum distanceof the spray pattern.

The sprinkler head gear 336 also drives a rotational sensor gear 340,which captures a diametric permanent magnet in line with a magneticrotational sensor 500 located external to the oscillator/diverterassembly 300. The gear 340 has a 1:1 ratio with the head gear 336,making it possible to electronically determine the corresponding angleof rotation of the nozzle 14. The oscillator gear train 334, head gear336, sensor gear 340 and pressure relief valve 338 are all rotatablycaptured within the oscillator chamber 332, which is pressurized at theoutput (nozzle) pressure. The electronic pressure sensor 400 is embeddedin the side wall of the oscillator chamber 332 and provides a means ofelectronically determining the nozzle pressure in real time. Note thatthe shaft 310 of neck 312 is the only component of theoscillator/diverter assembly 300 that penetrates a water chamber toatmosphere with a rotating component and, therefore, requires a seal;supplied here by an O-ring 344. Other than the supply input 320 and theshaft 310, the entire device is hermetically sealed. The frictionintroduced by the O-ring seal 344 is easily overcome by the torqueproduced by the gear ratio (approximately 500:1) of the oscillator drivetrain 334.

FIGS. 18-20 show external views of the diverter components. The motor302 of the external portion of the magnetic coupling 304 is used todrive the mechanism. The external rotation is transferred to theinternal portion of the assembly, which includes an armature 346 thatdiverts the water flow through one of two ports 322, 324 into theturbine chamber 328.

The input water flow is through input port 320. This supplies waterunder pressure to the diverter chamber 318. The control input is via theexternal components of the magnetic coupling 304, which changes theposition of the armature 346 (FIGS. 20-23) inside the diverter chamber318. The position of the armature 346 determines which port 322, 324 thewater flows through into the turbine chamber 328. As the water flowsacross the turbine wheel 314 the water continues to flow through theboundary wall 330 into the oscillator chamber 332 via ports 333. Theturbine 314 rotates and provides the mechanical input to the gear train334 via a small drive gear 348. A relief valve port 350 further allowsexcess pressure to release water through to the sprinkler neck 312,limiting the speed of the turbine 314.

FIGS. 20-21 shows the control input into the diverter armature 346. Themotor gear 352 drives the magnet gear 354, which has a square hole thatcaptures the external magnet 356. The external magnet 356 ismagnetically coupled to the internal magnet 358 across the boundary wallof the diverter chamber 318. The diverter boundary wall has a round well360 incorporated into it that captures the armature 346. As the externalmagnet 356 is rotated, the internal magnet 358 is rotated accordingly.Since it is captured in a square socket in the armature 346, thearmature 346 is also rotated in correspondence with the magneticcoupling. When the magnets 356, 358 are in phase, the north and southpole of the external magnet 356 is aligned with the south and northpoles of the internal magnet 358. In this relative position, themagnetic force vector is entirely normal to the boundary and the magnetsare attracted to each other. As the motor gear 352 continues to rotate,the armature 346 contacts one of the stops 362 a, 362 b, preventing anyfurther rotation of the armature 346. As the external magnet 356continues to rotate, the magnets become out of phase. When they are outof phase by 90 degrees, there is no longer a net magnetic force normalto the boundary, so the force vector is entirely rotational. As theexternal magnet 356 continues to rotate putting it greater than 90degrees out of phase with the internal magnet 358, the magnets begin torepel each other. As described previously, the external magnet 356 isfree to move normal to the boundary, so it is pushed away from theboundary and transfers the repulsive magnetic force through the magnetadapter 364 to the limit switch 366. At some point, when the phase angleis between 90 and 180 degrees, the force becomes strong enough toactivate the limit switch 366, which is electronically detected. Uponthe detection, the motor 302 is stopped and then reversed, which causesthe phase angle to decrease. At some point, when the phase angle is lessthan 90 degrees, the magnetic force becomes attractive again and themagnet 356 moves back toward the diverter boundary, releasing the limitswitch 366. Again, the deactivation of the limit switch 366 is detectedelectronically, and the motor 302 is stopped and locked. At thisposition, the phase angle is, generally, still greater than zero. In thefigure, the external magnet 356 is shown to be 45 degrees out of phasewith the internal magnet. In this state, the magnetic force vector isholding the armature 346 against the diverter boundary and against thestop 362, which is situated as to locate the armature plug 368 over oneof the output ports 322, 324 to the turbine chamber 328.

FIGS. 21-23 show the armature 346 being held in position against a stop362, which holds the armature plug 368 in line with one of the ports322, 324 (blocking the port) into the turbine chamber 328. Blocking oneport causes the water to flow into the opposite port. The pressurizedwater is directed onto the blades of the turbine 314 through thecorresponding port outlet. In this figure, the turbine 314 would rotatecounter-clockwise, as viewed from above. Rotating the armature 346 tothe opposite stop would cause the plug 368 to block the opposite port,which would cause water to flow through the other port and the turbine314 would rotate in the clockwise direction. It is this mechanism thatallows the rotation direction of the oscillator to be controlledelectronically. Note that it is possible to turn the motor 302 so thatthe armature 346 is in a position midway between the ports (position notshown). In this state, the water flows equally between the two ports322, 324 and the net pressure at the two port outlets is approximatelythe same and the turbine 314 does not rotate. One exemplary method ofachieving this state is by measuring the time it takes to drive themotor 302 from one stopped position to the other and then by rotatingthe motor 302 from one stopped position toward the other for half ofthat duration. Thus, the control is able to effect three states:rotation clockwise, rotation counter-clockwise and stationary. Otherpossible methods include the use of artificial intelligence (AI)learning algorithms which learn and adjust motor timing. AI typelearning algorithms are effective for this type of implementationbecause of the unpredictable nature of water in mechanical systems.

Another benefit to the present smart sprinkler arrangement is that thesprinkler system will never get stuck due to low water pressure. Oneproblem with purely mechanical sprinklers is that they require a minimumwater pressure to operate. There is friction in the water motormechanism, so you have to turn up the water pressure to some minimumamount to overcome that or it won't rotate. It can even be hard topredict because that point can be a little different along the rotation.Also, the mechanical actuator for changing direction requires an evengreater pressure to overcome the force involved in moving the actuator.Moreover, the supply pressure can change, so that a drop in pressure cancause a sprinkler to stop rotating even if it was when it was set up.

The present system has the same problem with friction of the waterpowered motor 308. Some minimum is required for rotation of the turbinewheel 314 to occur. With the present sprinkler system 10, the point ofdirection change is detected by a sensor and the change of direction isaccomplished via an electric motor. Neither introduces additionalfriction or requires water pressure. In addition, it can detect whetherthe sprinkler head is rotating (rotational sensor gear 340) and canautomatically raise the pressure (valve 200) until it starts rotating.It also raises the pressure automatically if the supply pressure dropsdue to outside factor (local water demand). This means that thesprinkler 10 will not get stuck. In fact, there really is no minimumpressure. The system will lower the pressure to a user set point andthen automatically raise it enough to rotate the sprinkler head 14. Oncerotation is detected, it will again lower the pressure to the user setpoint. The system won't generate a simple arc in this mode, as it wouldwith a higher pressure, but it will apply water at the set range, and itwon't get stuck. Note that this assumes that the supply pressure isgreater than the minimum required pressure. If this is not satisfied,the sprinkler can detect the condition and shut itself off completely,abandoning the user pattern until such time as the supply pressure isrestored. Similarly, if a water pattern was configured that includes amaximum water pressure that cannot be achieved at the time of runningthe pattern, the sprinkler can automatically skip over those portions ofthe pattern that cannot be achieved and still execute the portions ofthe pattern that can. Thus, the sprinkler can come as close tosatisfying the desires of the user as is possible.

Accordingly, it can be seen that the present system 10 provides severalunique and novel improvements over systems of the prior art,particularly with respect to sealed chamber magnetic couplers andswitching mechanism which eliminate the need for high friction seals forrotating parts and which also reduce power needs for rotating componentswithin the sealed chambers.

Having thus described certain particular embodiments of the invention,it is understood that the invention defined by the appended claims isnot to be limited by particular details set forth in the abovedescription, as many apparent variations thereof are contemplated.Rather, the invention is limited only by the appended claims, whichinclude within their scope all equivalent devices or methods whichoperate according to the principles of the invention as described.

What is claimed is:
 1. A pilot valve assembly comprising: a valve bodyhaving input and output chambers and a valve seat spanning saidchambers; a control body connected to said valve body, said control bodyhaving a control chamber therein and a control chamber wall oppositesaid valve body; a diaphragm seated in said valve seat, said diaphragmseparating said control chamber from said input and output chambers; aninput pilot hole extending through said diaphragm connecting said inputchamber with said control chamber; an output pilot hole extendingthrough said diaphragm along a central axis thereof and connecting saidcontrol chamber with said output chamber; a control assembly comprising:a lead screw rotatably mounted within said control body coaxially withsaid axis of said output pilot hole and normal to said control chamberwall; a plug on a terminal end of said lead screw adjacent said outputpilot hole, whereby rotation of said lead screw linearly moves said plugrelative to said pilot output pilot hole; a magnet adapter mounted on aproximal end of said lead screw; an internal magnet received in saidmagnet adapter aligned on said axis of rotation; an external couplingbody rotatably mounted on an exterior surface of said control chamberwall, said external coupling body having an axis of rotation alignednormal to said chamber wall and coaxial with said axis of rotation ofsaid lead screw; an external magnet received in a socket in saidexternal coupling body on said axis of rotation; said internal andexternal magnets each having north and south poles aligned parallel tothe chamber wall and in phase with each other; and wherein said internalmagnet is magnetically coupled to said external magnet and said internalmagnet, magnet adapter and lead screw are correspondingly rotated byrotation of said external coupling body and external magnet.
 2. Thevalve assembly of claim 1 further comprising a sensor configured andarranged to sense an extent of travel of said lead screw within saidcontrol chamber.
 3. The valve assembly of claim 1 further comprising areversible motor driving rotation of said external coupling body.
 4. Thevalve assembly of claim 3 wherein said external coupling body comprisesa coupling gear and further comprising a motor gear engaged with saidcoupling gear for driving rotation of said coupling gear.
 5. The valveassembly of claim 3 further comprising a pressure sensor incommunication with the output chamber, said valve assembly including acontrol system receiving a sensed pressure within said output chamberand controlling said motor to adjust said pressure responsive to saidsensed pressure.
 6. The valve assembly of claim 4 further comprising apressure sensor in communication with the output chamber, said valveassembly including a control system receiving a sensed pressure withinsaid output chamber and controlling said motor to adjust said pressureresponsive to said sensed pressure.
 7. A pilot valve assemblycomprising: a valve body having concentric input and output chambers anda valve seat spanning said chambers; a control body connected to saidvalve body, said control body having a control chamber therein and acontrol chamber wall opposite said valve body; a flexible diaphragmseated in said valve seat, said flexible diaphragm separating saidcontrol chamber from said input and output chambers; a stabilizer plateconnected to said diaphragm at a plurality of circumferentially spacedlocations; an input pilot hole extending through said diaphragm and saidstabilizer plate connecting said input chamber with said controlchamber; an output pilot hole extending through said diaphragm andstabilizer plate along a central axis thereof and connecting saidcontrol chamber with said output chamber; a control assembly comprising:a lead screw rotatably mounted within said control body coaxially withsaid axis of said output pilot hole and normal to said control chamberwall; a plug on a terminal end of said lead screw adjacent said outputpilot hole, whereby rotation of said lead screw linearly moves said plugrelative to said pilot output pilot hole; a magnet adapter mounted on aproximal end of said lead screw; an internal magnet received in saidmagnet adapter aligned on said axis of rotation; an external couplingbody rotatably mounted on an exterior surface of said control chamberwall, said external coupling body having an axis of rotation alignednormal to said chamber wall and coaxial with said axis of rotation ofsaid lead screw; an external magnet received in a socket in saidexternal coupling body on said axis of rotation; said internal andexternal magnets each having north and south poles aligned parallel tothe chamber wall and in phase with each other; and wherein said internalmagnet is magnetically coupled to said external magnet and said internalmagnet, magnet adapter and lead screw are correspondingly rotated byrotation of said external coupling body and external magnet.
 8. Thevalve assembly of claim 7 further comprising a sensor configured andarranged to sense an extent of travel of said lead screw within saidcontrol chamber.
 9. The valve assembly of claim 8 wherein said sensorcomprises a mechanical switch which cooperates with said externalcoupling body.
 10. The valve assembly of claim 7 further comprising areversible motor driving rotation of said external coupling body. 11.The valve assembly of claim 10 further comprising a sensor configuredand arranged to sense an extent of travel of said lead screw within saidcontrol chamber.
 12. The valve assembly of claim 11 wherein said sensorcomprises a mechanical switch which cooperates with said externalcoupling body.
 13. The valve assembly of claim 12 wherein saidmechanical switch is a limit switch mounted on said axis of rotation ofsaid external coupling body adjacent to said external magnet, saidexternal magnet being slidably movable within said socket of saidcoupling body along said axis of rotation, wherein said external magnetis repulsed by said internal magnet and slidably moves within saidsocket into engagement with said limit switch when said lead screwengages a fully open stop or fully closed stop preventing furtherrotation of said lead screw and said internal magnet and said externalcoupling body continues to rotate, thereby forcing said external magnetout of phase with said internal magnet and creating a repulsive forcepushing said external magnet away from said control chamber wall. 14.The valve assembly of claim 10 wherein said external coupling bodycomprises a coupling gear and further comprising a motor gear engagedwith said coupling gear for driving rotation of said coupling gear. 15.The valve assembly of claim 13 wherein said external coupling bodycomprises a coupling gear and further comprising a motor gear engagedwith said coupling gear for driving rotation of said coupling gear. 16.The valve assembly of claim 10 further comprising a pressure sensor incommunication with the output chamber, said valve assembly including acontrol system receiving a sensed pressure within said output chamberand controlling said motor to adjust said pressure responsive to saidsensed pressure.
 17. The valve assembly of claim 11 further comprising apressure sensor in communication with the output chamber, said valveassembly including a control system receiving a sensed pressure withinsaid output chamber and controlling said motor to adjust said pressureresponsive to said sensed pressure.
 18. The valve assembly of claim 12further comprising a pressure sensor in communication with the outputchamber, said valve assembly including a control system receiving asensed pressure within said output chamber and controlling said motor toadjust said pressure responsive to said sensed pressure.
 19. The valveassembly of claim 13 further comprising a pressure sensor incommunication with the output chamber, said valve assembly including acontrol system receiving a sensed pressure within said output chamberand controlling said motor to adjust said pressure responsive to saidsensed pressure.